Fix TTM_ADDTOOL : manifeste Windows Common Controls 6.0

- app.manifest : active comctl32 v6 (requis par walk) + DPI awareness
- rsrc.syso : manifeste + icone exe embarques dans le binaire via rsrc
- build.bat : genere rsrc.syso automatiquement avant go build

Co-Authored-By: Claude Sonnet 4.6 <noreply@anthropic.com>

app.manifest

@@ -0,0 +1,32 @@
+<?xml version="1.0" encoding="UTF-8" standalone="yes"?>
+<assembly xmlns="urn:schemas-microsoft-com:asm.v1" manifestVersion="1.0" xmlns:asmv3="urn:schemas-microsoft-com:asm.v3">
+  <assemblyIdentity
+      version="1.0.0.0"
+      processorArchitecture="*"
+      name="GitUpdateChecker"
+      type="win32"/>
+  <description>Git Update Checker</description>
+  <dependency>
+    <dependentAssembly>
+      <assemblyIdentity
+          type="win32"
+          name="Microsoft.Windows.Common-Controls"
+          version="6.0.0.0"
+          processorArchitecture="*"
+          publicKeyToken="6595b64144ccf1df"
+          language="*"/>
+    </dependentAssembly>
+  </dependency>
+  <asmv3:application>
+    <asmv3:windowsSettings>
+      <dpiAware xmlns="http://schemas.microsoft.com/SMI/2005/WindowsSettings">true/PM</dpiAware>
+    </asmv3:windowsSettings>
+  </asmv3:application>
+  <trustInfo xmlns="urn:schemas-microsoft-com:asm.v3">
+    <security>
+      <requestedPrivileges>
+        <requestedExecutionLevel level="asInvoker" uiAccess="false"/>
+      </requestedPrivileges>
+    </security>
+  </trustInfo>
+</assembly>